An image sensor has sensitivity not only to visible light but also to infrared light. Therefore, in a case where photographing is performed using a camera with an image sensor under a light source including much infrared light, color reproduction is impaired by the influence of the infrared light. Accordingly, it has been proposed to achieve good color reproduction by providing a camera with an infrared (IR) cut filter (IRCF) that shields infrared light.
However, it is important to improve the night-time sensitivity of a surveillance camera or the like and thus secure visibility. Therefore, there is a camera including a mechanism that inserts and removes an IR cut filter and removes the IR cut filter during night-time and the like (for example, refer to Patent Document 1).
With such a camera including a mechanism that inserts and removes an IR cut filter, an amount of transmission of an infrared light component greatly changes, depending on the presence or absence of the IR cut filter. Therefore, particularly when infrared light is projected, blown-out highlights occur at the moment the IR cut filter is removed. As a result, the visibility of a captured image decreases.
Additionally, in a case where the insertion and removal of the IR cut filter is controlled on the basis of exposure information of the image sensor, it is necessary to prevent hunting at insertion and removal of the IR cut filter by differentiating illuminance at the removal from illuminance at the insertion. As a result, even in a case where the illuminance becomes high enough, the IR cut filter may not be inserted and a monochrome image may remain output as a captured image.